As a conventional woven slide fastener, according to Japanese Patent Application Laid-Open (JP-A) No. 10-5010 (Patent Document 1) for example, a continuous fastener element row which is knitted onto a fastener element attaching portion using a single-bed-type warp knitting machine having a single needle bed is fixed by fixing chain knitting yarns of two wales or more, each needle loop of each fixing chain knitting yarn presses a leg of each element of the continuous fastener element row from above toward a ground structure, warp in-laid yarns are intermingled with, warp inserted and knitted onto at least some of sinker loops of a sinker loop group to stabilize the fastener element row in size, and to prevent disengagement of the fastener element.
JP-A No. 2002-360316 (Patent Document 2) discloses a woven slide fastener which knits likewise using a single-bed-type warp knitting machine, its fastener element attaching portion is knitted by fixing knitting yarns and other knitting yarns which sandwich and fix upper end lower legs of each fastener element in a front-back direction, composite fiber yarns including heat-shrinkable fiber material and heat-fusion fiber material are employed as a portion of the configuration yarns, the heat-shrinkable fiber material is shrunk by heating treatment, the heat-fusion fiber material is fused on the other peripheral configuration yarns, and the fastener element attaching portion is highly densified to enhance a fastening force with respect to the fastener element. Even if yarns which configure the element attaching portion of the fastener tape are cut by interference with a sewing needle at the time of sewing operation, a fray is not generated, and a fastener element row at that portion is not separated from the fastener tape.
The fastener element of the fastener element attaching portion of the woven slide fastener which knits using the single-bed-type warp knitting machine disclosed in Patent Documents 1 and 2 is attached by pressing the leg of the fastener element toward the ground structure by the needle loop of the fixing chain knitting yarn, and the fastener element is supported by a sinker loop of the fixing chain knitting yarn and warp in-laid yarn which configure the ground structure. Hence, the density of ground structure itself is likely to be coarse, and since the sinker loop and the weft in-laid yarn are likely to expand and shrink in the length direction of the tape, the fastener element can not be stably fixed. Further, since tension greater than those of other knitting yarns is applied to the fixing chain knitting yarn, the sinker loop is pulled up along a side surface of the leg of the fastener element by the needle loop. Therefore, the ground structure portion is likely to be corrugated into an uneven surface, and outward appearance becomes poor.
In Patent Documents 1 and 2, to strongly fix the fastener element to the fastener element attaching portion knitted by the single-bed-type warp knitting machine, or to improve the poor outward appearance, countermeasure is taken in addition to normal knitting. For example, warp in-laid yarn is inserted in between sinker loops which are connected to each other in a tape length direction of the fixing chain knitting yarn in a zigzag form, or composite fiber yarns including heat-shrinkable fiber material and heat-fusion fiber material are used as the fixing chain knitting yarn.
To solve the problem of the single structure using the single-bed-type warp knitting machine, JP-A No. 8-228813 (Patent Document 3), JP-A No. 8-299034 (Patent Document 4) and JP-A No. 2005-230040 (Patent Document 5) propose that a fastener element attaching portion is knitted with double structure using a double-bed-type warp knitting machine such as a double raschel knitting machine having two rows of needle beds. According to any of the fastener element attaching portion of the slide fastener described in Patent Documents 3 to 5, the same fixing chain knitting yarn is knitted by double structure using front and back two rows of knitting-needles.
This will be described specifically. According to the fastener element attaching portion disclosed in Patent Documents 3 to 5, its ground structure is knitted using a back needle row, and its fixing chain knitting yarn is knitted using front and back two rows of needle beds. Hence, a needle loop formed by the front needle row of the fixing chain knitting yarn is knitted to straddle the fastener element and in a subsequent course, a needle loop is formed by the front needle row, and a needle loop formed by the front needle row intermingles with the former needle loop, i.e., the needle loop is knitted by a so-called double structure. These are alternately repeated. That is, a needle loop for pressing a fastener element is formed using the front needle row on a leg of the fastener element disposed between two rows of courses, and during a subsequent course, when a needle loop of ground configuration knitting yarn is formed by the back needle row, the fixing chain knitting yarn is formed on the same back needle row by intermingling a needle loop of a next course with the former needle loop of the ground configuration knitting yarn at the same time.
Knitting yarns used for aground structure knitted by the back needle row in the fastener element attaching portion disclosed in Patent Documents 3 to 5 are warp knitting yarns of any of ground structure chain knitting yarns, tricot knitting yarns and second warp knitting yarns or a combination of them. A warp in-laid yarn or a weft in-laid yarn is inserted into a sinker loop of knitted stitches which are connected in a longitudinal direction or a width direction of the ground structure knitted by these knitting yarns.
Since the fixing chain knitting yarn is knitted onto the fastener element attaching portion such that the double structure using a double-bed-type warp knitting machine is included, the fastener element row is strongly attached to an edge portion on the longitudinal side of the warp knitting fastener tape stably in size, elongation of the fastener element attaching portion is suppressed at the same time, disengagement when the fastener chain is folded is eliminated, and smooth engagement can be carried out.